Air-pump.



P. J. BODE.

AIR PUMP.

7 APPLICATION FILED DEC.'2I,19l 2- RENEWED JUNE 1, 1915. 1,148,073.

Patented July 27, 1915.

3 SHEETS-SHEET I N VEN TOR. Pezer J- Bode WITNESSES:

ATTORNEY.

P. J. BODE.

AIR PUMP.

APPLICATION FILED DEC. 21. 1912. RENEWED JUNE 7. 1915.

Patented July '27, 1915.

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INVEVTOR E Peze/"rf-Bode- BY I ' ATTORNEY.

COLUMBIA PLANOGRAPH P. J. BODE.

- AIR PUMP.

APPLICATJON FILED DEC. 21. I912. RENEWED JUNE 7, 1915.

I V 14%,073, Patented July 27,1915.

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PETER JACOB BODE, OF S'Ifl LOUIS, MISSOURI, ASSIGNOR F 0NE-EIGHTH T0 FREDERICK KARL HEUSLER, QF ST. LOUIS, MISSOURI.

. AIR-PUMP.

Specification of Letters Patent. Patented July 27, 1915.

Application filed December 21, 1912, Serial No. 738,056. Renewed June 7,1915. Serial No. 32,732.

To all whom it may concern Be it known that I, PETER J. Bonn, citizen of the United States, residing at St. Louis, State of Missouri,have invented certain new and useful Improvements in Air- Pumps, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming a part hereof.

My invention has relation to improvements in air-pumps; and it consists in the novel details of construction more fully set forth in the specification and pointed out in the claims. 7

In the drawings, Figure 1 is a side elevation of the pump with its double piston raised to the end of its up-stroke, parts being broken away; Fig. 2 is arear elevation with the pistonsat the end of their downstroke; Fig. 3 is a vertical middle section on the line 33 of Fig. 2 with certain parts in elevation; Fig. 4: is a horizontal cross-section on the line 4:& of Fig. 1; Fig. 5 is a horizontal crosssection on the line 55 of F 1; Fig. 6 is a combined side'elevation, and a vertical section on the order of Fig. 3, showing however, the outer or hollow piston out of commission, and the inner piston partly elevated or substantially at midstroke; Fig. 7 is an elevation of the valvecasing detached; Fig. 8 is a vertical section on the line 88 of Fig. 7; Fig. 9 is a top plan of the inner pump-piston; Fig. 10 is a horizontal cross-section on the line 1010 of. Fig. 6; and Fig. 11 is an enlarged sectional detail on the linell-ll of Fig. 8.

The object of my invention is to construct an air-pump capable ofoperation with either a single piston or with two pistons acting as a unit, the selection (of piston) depending on the service which the pump is intended to perform. lVhen the pump per-. forms the function of a compressor, it may be started with both pistons operating as a unit or single piston, thereby permitting the handling of comparatively large volumes of air without material resistance to thepiston.

As the pressure inthe storage tank or reser-- voir (into which the air is d1scharged) rises,

one of the pistons (the larger one) maybe put out of commission, the smaller piston being depended on to dothe work of compression, as it is better adapted to overcome the increased resistance resulting from higher pneumatic pressures.

A further object of the invention is to provide special air cooling columns for the walls ofthe respective pistons and cylinder to prevent overheating of the cylinder walls; toprovide means for automatically adjusting the speeds of the piston strokesto the rate of compression to which the charge of air or gas operated on is subjected within the pump-cylinder, therebyrninimizing the tendency of overheating of the parts by a proper control of the rate of compression and hence of the rate of increase of the temperature due to such compression.

A further object is to provide a pump with a lever-operated piston, the contour of the lever being such as to develop a maximum leverage with a restricted length of leverarm; one wherein the leverage progressively increases with an increase in the resistance; and finally to provide a pump possessing further and other structural features the advantages ofwhich will be better apparent from a detailed description of the invention which is as follows:

Referring to the drawings, 0 represents the pump-cylinder the same terminating in a basal flange (1 provided with supporting legs L andan upper flange a, and having its walls reinforced between the flanges by ribs 1'. the outer tubular piston P provided with a series of peripheral longitudinal grooves 7L terminating near the bottom of the piston in a transverse annular groove on, said grooves forming collectively an air jacket between the piston and cylinder walls when the piston is within the cylinder (Fig. 10). The lower terminal of the piston P is reduced to accommodate a series of packing rings (Z, the cylinder being closed at the bottom by the flange of the valve-casing 1 to which reference will presently again be made, a packing disk d being interposed be tween the flange t and the cylinder flange a to which the valve-casing 1 is bolted. The

' upperend of the piston P terminatesin a Operating within the cylinder C is I of aiinement.

ment of the piston in its down stroke, the head arresting the piston by engaging the top of the cylinder. Within the outer hollow piston P there is free to operate an inner smaller piston P preferably hollow and closed at the bottom, the walls being likewise fluted or provided with longitudinal grooves h forming air passages with the walls of the piston P, said grooves h terminating a bottom annular groove on, and communicating with the interior of the hollow piston through ports 2 (Figs. 6, 10). To the bottom of the piston P is secured by means of a screw 3, a reduced piston stem or plunger P for operating in the correspondingly reduced lower passage-way or bore A of the outer piston. Around the stem P are placed )acking rings (2, the same bearing against the bottom of the member P. The members P, P, form in effect a single inner piston, though for convenience and where necessary the member P will be referred to as the stem or plunger, and the member P as the main piston section or inner piston proper.

. The upper end of the inner piston terminates in a'platform at assuming the form of two lobes or sections (Fig. 9) across which is disposed a pin 15 which has mounted thereon between the lobes an anti-friction roller 6, the piston-walls being suitably contoured to accommodate the roller (Fig. 3). From the lobes or sections 4, 4, extend brackets or arms 7, 7, between the upper ends of which is mounted on a spindle 8, a second anti-friction roller 9, the centers of the two rollers (6, 9) being vertically out To the rear of the flange a are bolted the arms or brackets 10, 10, between which is pivoted one end of the curved lover or pitman 11 terminating in a handle H in rear of the pump, the lever passing freely between the rollers 6, 9, mounted on the upper terminal platform 1, a, of the inner piston P. Disposed around the cylinder C between the flanges (L, a, are a series (four in the present case) of tubes 12 opening through the flanges, in which freely operate'the rods 13 depending from the platform 1 (the same being driven into the holes 0, Fig. 9), the arrangement serving to guide both pistons or the inner piston when operating alone and when detached from the outer tubular piston P in which it is telescopically mounted. The sides of the piston-head 0 are provided with studs or bosses 141, the platform l of the inner telescoping piston being provided with similar studs or bosses formed by the terminals of the pin 15; and when it is desired to couple the two pistons suitable links 16 are slipped over the respective studs or bosses 11, 15 (Figs. 1, 2) the links being prevented from working ofl the studs by a detachable spring wire yoke '17 the ends of which are received by suitable holes 2' (Fig. 1), the yoke drawing the links together and maintaining them in position on their studs. When thus coupled, the two pistons P, P, (P) operate as a unit or as a single piston, the extension P of the inner piston closing the passage A formed in the lower end of the outer piston P. On the other hand, the flange a of the cylinder is provided with studs or bosses 18 which may be cou pled to the studs 14 of the outer piston by means of links 16 passed over the studs 14, 18 respectively, and secured to the studs 14 by screws 19 (Fig. 6). hen this is done the outer piston P becomes locked to the cylinder, and, by removing the links 16 and the yoke 17, leaves the inner piston free to operate alone, the outer piston then'serving as a bushing or cylinder for the inner piston (Fig. 6). It follows therefore that either the inner piston can operate alone, or both pistons may be coupled together and operate as a unit or single piston.

The valve-easing 1 is provided with a plate 20 with which is integrally formed a bushing 21 inserted into the casing, the bushing being provided with an ordinary intake gravity check-valve 22 the stem 23 of which operates loosely throughthe plate 20 and is provided on the outside with adjustable nuts 24 for limiting the throw of the valve. The valve controls the influx of air through the intake opening 25 (to which a pipe when necessary may be attached). Likewise bolted to the casing 1 is a plate 20 with which is integrally formed a 'stopbushing 21 in which operates the stem 26 of a discharge check'valve 27 the stem being provided with pins 28 guided in slots 29 of the bushing, a compression spring 30 in the bushing engaging the stem of the valve and seating the latter after the valve has been unseated with any given discharge of air resulting from a downstroke of the piston (or pistons). The valves are not herein claimed however, being well under stood in the art.

The discharge opening 25 (Fig. 8) may be coupled to a T 31 from which may lead piping 32 to any suitable reservoir or compressedair storage tank, a second branch 32 being provided with T 33 temporarily closed up until such time as it may be availed of for coupling other piping thereto when necessary.

he ports respectively controlled by the valves 22, 27, are represented by numerals 34:, 35, in Fig. 5. Between the valve-casing 1 and the plates 20, 20, is interposed a packing 36 (Fig. 8).

The operation of the pump is substantially as follows :By seizing the handle H the lever 11 may be oscillated up and down, and operating as it does between the rollers 6, 9, it reciprocates the inner piston. If the two pistons P, P, (P are coupled together by the links 16, they reciprocate as a unit or single piston. With each up-stroke of the double piston thus formed, air is drawn into the cylinder through the intake opening 25 and port 3%; with each down-stroke air is expelled through the port 35 and outlet 25, and through the pipe 32 and stored in any suitable receiver (not shown), or the pump may be used to inflate automobile tires, or put to any purpose whatever. If, on the other hand the two pistons are detached from one another so as to leave the smaller or inner piston free, and the outer tubular piston P be anchored to the cylinder by the links 16 as described, then only the inner piston will be reciprocated, the air being drawn into the outer piston as a cylinder through the passage A, and expelled therefrom with a down-stroke of such inner piston. The intake and discharge valves 22 27, of course, perform their legitimate functions in either case, their action beingin no wise changed with the operation of either the single or double piston.

I11 practice, the double piston (P, P, P) is used when a storage tank or receiver is first being charged with compressed air and when the resistance or back pressure on the area of the combined pistons may be readily overcome by the operator who works the lever 11 (the lever may of course, be operated by motive power). As the pressure in the tank increases however. the outer piston P is anchored to the cylinder, and only the inner or single piston is worked, for then the power with which the lever 11 be operated is considerably reduced owing to the reduction of the pressure or resistance exerted against the smaller area of the end of the plunger 1?. By virtue of the air channels 7t, 7t, and ports 2, not only are the cylinder and piston walls kept cool owing to the free circulation of air, but the interior of the inner hollow piston P is kept cool. The maximum velocity imparted to the piston (single or double) is when the rollers 6, 9, are traversing the lever 11 along the portions of maximum curvature, that .is to say, the intermediate portion. As the lever approaches the lower end of its oscillation the rectilinear movement imparted to the piston is at its minimum, owing to the short length of lever arm then available, this feature being important especially in connection with the down-stroke of the piston. As the end of the down-stroke is being approached, the air is undergoing its greatest compression (as it unseats the valve 27) and hence the greatest rise in temperature occurs (it being well known that when a gas is compressed heat is evolved). In ordertherefore to prevent overheating of the pump as a result of a too rapid compression of the air (or other gas) and a consequent rise in 'temperature flowing from such compression, the speed of the piston is automaticallyreduced as it approaches the limit of its downward'or COIH'. pressionstroke. By thus retarding the speed of the piston at the critical moment, the rise in temperature is checked, because the compression is correspondingly retarded. In fact, with -my present pump air may be pumped into a reservoir under several hundred pounds pressure and thewalls of the cylinder will remain cool. This cooling results not only from the air channels and free circulation accorded the air around and between the walls of the pistons and cylinder, but from the differential speed imparted to the piston (or pistons) by the curved or bowed lever or pitman 11, the concave edge of which faces the piston. This speed decreases (at the end of the compression or expulsion stroke) as the pressure of the air increases, that is to say, it'is in an inverse ratio to the increase in pressure. The pump may of course, serve to operate on any kind of gas, fluid, or liquid.

Having described my invention, what I claim is 1. In a pump, the combination of a cylinder, an outer piston having one end projecting beyond the cylinder, studs extending from opposite sides of said projecting end of the piston, corresponding studs on the cylinder, detachable links engaging the respective studs of the piston and cylinder for locking the piston to the cylinder, and an inner piston operating in the outer piston thus locked to the cylinder.

. 2. In a pump, the combination of a cylinder, a piston, a roller mounted at one end of the piston, a second roller carried by the piston beyond and out of alinement with the first roller, a lever pivoted at one end to the pump cylinder and having a bowed portion passing between the rollers, the concave edge of the bowed portion of the lever being toward the piston, the latter reciprocating with any oscillations imparted to the lever.

3. In a pump, the combination of a cylinder, a reciprocating piston therefor, a series of tubular guides disposed around the cylinder walls in lines parallel to the reciprocations of the piston, and rods carried by the piston and operating through the tubes for guiding the piston in its movements when retracted from the cylinder.

4. In a pump, the combination of a cylinder, an outer tubular piston terminating at one end in a reduced passage-way, an inner piston terminating in a reduced member adapted to close said passage-way, and means for locking the outer piston to the cylinder whereby the inner piston may operate alone, and a valve-casing provided with suitable intake and discharge check-valves positioned in the path of said passage-way.

5. In a pump, the combination of a cylinder, an outer tubular piston having longitudinal peripheral grooves, an inner hollow pistonlreceived by the outer piston and provided with longitudinal peripheral grooves, suitable ports leading fromthe inner terminals of said grooves to the interior of the inner hollow piston, and-a member coupled to the hollow inner piston for closing one end of the outer tubular piston.

In testimony whereof I affix my signature, in presence of two witnesses.

PETER JACOB BODE. .-Witnesses H. 'MINTOR, V. A. SHIVELBI-NE.

Copies of this patent may be obtainedior five cents each, by addressing the Commissioner of Patents. Washington, 1). C. 

